The invention is based on a measuring instrument for contactless detection of an angle of rotation. DE-OS 196 34 281.3 has disclosed a sensor which is disposed in three superposed planes. The rotor constitutes the middle plane, wherein it is comprised of the supporting plate for a permanent magnet. The supporting plate itself is comprised of magnetically nonconductive material so that the magnetic flux travels via the two other planes, i.e. the stator, and is dispersed with the aid of two spacers which are disposed between the two planes of the stator. The shaft or the projections of a shaft that is attached to the rotor has no influence on the magnetic flux. With the sensor, a relatively large angular range can in fact be measured without a change of sign, but it is relatively large in terms of the axial direction due to being constructed of three parallel planes.
Furthermore, in potentiometers, it is known to produce a broken measurement line by subdividing the contact paths in the vicinity of the flattening.
The measuring instrument for contactless detection of an angle of rotation according to the invention has the advantage over the prior art that the sensor has a relatively small size in the axial direction. It is comprised of only two planes. The supporting plates of the permanent magnet which represents the rotor is simultaneously also used to convey the magnetic flux. Furthermore, the shaft or axle supporting the rotor is included in the conduction of the magnetic flux, as a result of which additional magnetic flux conducting parts are rendered unnecessary. Furthermore, this design reduces the number of parts and the assembly costs involved with them.
By varying the length of the magnet or dividing it into individual sections, it is simple to produce a measurement curve with one or more flattenings.
Due to its simple design, the sensor can be integrated with a relatively low assembly cost into various systems, e.g. a throttle measurement device, a pedal module for a gas pedal-travel sensor or can be used as an independent sensor in throttle valve transmitters or a body spring compression device.